With semiconductor technology development, more millimeter wave ICs (integrated circuits) come to the final production tests. To realize the production tests, a thick probe interface board (PIB) for wafer tests or a thick device interface board (DIB) for module tests is needed. Due to their high profile, which can be an obstacle to the wafer or the module handler, connectors can only be mounted on the side of PIB or DIB opposite to the side for the probe card or socket. This requires through PCB (printed circuit board) vias with good signal integrity for propagating the signals from one side to another.
However, large thicknesses of the PIB or DIB (e.g., 100 mil or larger) and the high application frequency (e.g., several tens of GHz to 100 GHz and beyond) make the through PCB vias no longer a short discontinuity for signals. To this end, the PIB or DIB needs to be carefully designed in order to accommodate thick boards and high frequencies.